select code
      ,substr(sys_connect_by_path(nm, ','),2) as paths
      ,code_p
  from (
select 1  code, '서울시' nm, 0    code_p from dual union all
select 2  code, '강남구' nm, 1    code_p from dual union all
select 3  code, '송파구' nm, 1    code_p from dual union all
select 4  code, '대치동' nm, 2    code_p from dual union all
select 5  code, '문정동' nm, 3    code_p from dual union all
select 6  code, '구로구' nm, 1    code_p from dual union all
select 7  code, '고척동' nm, 6    code_p from dual union all
select 8  code, '개포동' nm, 2    code_p from dual union all
select 9  code, '의정부' nm, null code_p from dual union all
select 10  code, '부산'   nm, 0    code_p from dual
)
where connect_by_isleaf = 1
connect by prior code = code_p
start with code_p = 0
        or code_p is null;

 감사합니다~

근데 저는 콤마로 구별하는게 아니구

decode로 칼럼을 나누려구요....ㅠㅠ

WITH t AS
(
SELECT 1 code, '서울시' addr, 0 code_p FROM dual
UNION ALL SELECT  2, '강남구',    1 FROM dual
UNION ALL SELECT  3, '송파구',    1 FROM dual
UNION ALL SELECT  4, '대치동',    2 FROM dual
UNION ALL SELECT  5, '문정동',    3 FROM dual
UNION ALL SELECT  6, '구로구',    1 FROM dual
UNION ALL SELECT  7, '고척동',    6 FROM dual
UNION ALL SELECT  8, '개포동',    2 FROM dual
UNION ALL SELECT  9, '의정부', null FROM dual
UNION ALL SELECT 10, '부산'  ,    0 FROM dual
)
SELECT REGEXP_SUBSTR(addr, '[^,]+', 1, 1) addr1
     , REGEXP_SUBSTR(addr, '[^,]+', 1, 2) addr2
     , REGEXP_SUBSTR(addr, '[^,]+', 1, 3) addr3
  FROM (
        SELECT SYS_CONNECT_BY_PATH(addr, ',') addr
          FROM t
         WHERE CONNECT_BY_ISLEAF = 1
         START WITH NVL(code_p, 0) = 0
         CONNECT BY PRIOR code = code_p
        )
;